More parents are providing significant financial support for their adult children even as they cope with the needs of their own aging parents, according to a new survey of the middle-aged “sandwich generation.”

The twin financial and emotional burdens on the one in seven Americans who are squeezed between their children and their parents have mounted since the recession, the Pew Research Center said in a report released Wednesday. In 2005, 20 percent of all middle-aged parents were the primary source of financial support for a grown child. Now, 27 percent of parents fit that description.

The increase is striking since the share of middle-aged adults with children and living parents has remained stable.

For at least three decades, sociologists have noticed a trend of more parents paying much of the freight until their children are well into their 20s, but the faltering economy has caused those numbers to spike.

“The causes include the difficulty young adults have finding decent employment and the longer time they take to get the education they need,” said Andrew Cherlin, a sociologist at Johns Hopkins University who studies families. “Until we figure out how to integrate young adults into the economy, their parents will be called upon to support them.”

The Pew survey of 2,500 adults found that nearly half the people ages 40 to 59 have given money in the past year to at least one child who is 18 or older. Many of them supported children still attending school. But almost half the parents who say they are the primary source of support for a grown child cite other reasons.

The findings reflect an evolution in the image of who makes up the sandwich generation. In the past, the burden typically was shouldered by a middle-aged woman who stayed at home caring for young children and aging parents. During the recession and the slow recovery, more adult children have returned home while they look for jobs. Even the percentage of married couples living in a parent’s home has returned to levels not seen since the turn of the 20th century.

Demographic changes are behind much of the shift, said Charles R. Pierret, director of longitudinal surveys at the Bureau of Labor Statistics, who has surveyed the sandwich generation. Longer life expectancy and delayed childbearing mean that more middle-aged people have dependent children and parents who are still living.

The change can have enormous financial implications for parents caught in the middle.

“There are concerns people are potentially taking money out of their retirement accounts, which is never a good option, to help support their adult children,” said Lynn Feinberg, a caregiving specialist for AARP. “Because of economic concerns, families are being challenged in ways we hadn’t conceived of even 10 years ago.”

She could be talking about Michelle, a District woman who asked that her last name not be published so she could speak candidly about intensely private family matters.

Michelle, 60, and her husband are still supporting their 29-year-old son and 25-year-old daughter. They pay the rent for their daughter’s apartment in Manhattan while she prepares to attend law school. They are subsidizing their son while he works at a low-paying job teaching English in Spain.

Michelle just returned after spending three months with her mother, who is 85 and lives in Florida. Her mother is physically healthy but is growing forgetful, and Michelle took leave of her job to spend time trying to persuade her to move north.

Michelle said she and her husband don’t take vacations anymore, just trips to help their children and her mother. Her husband would like to slow down, she said, but is hesitant to retire when they have so many financial obligations.

It’s very different from when she reached adulthood. She left home after high school and never returned to live in her parents’ home. She was living on her own until she married at age 24.

“Kids are dependent on parents a lot longer today,” she said. “I don’t know if it has to do with the economy or the way we raise them.”

But in the neighborhood where she has lived for more than 30 years, Michelle said, she knows her dilemma is a common one.

“Kids transition in and out,” she said. “They graduate from high school, go to college, come home, find a job, get married, divorced and come back, sometimes with kids and pets. One thing I’ve learned is, your house is a revolving door.”